The presently disclosed embodiments are directed to the field of vehicle seats, and particularly such seats having head rests. The embodiments relate to adjusting the contour of the seat back to promote comfort and safety of the user.
Adjustable vehicle seats and positionable head restraints or head rests are well known in the art. For example, systems are known for adjusting seat position based upon the individual and driving conditions. Such systems provide for automatic adjustment of the seat back, among other parameters.
It is also well known to design vehicle seats and head rests to improve protection to occupants from rear end collisions and whiplash. Various patents are known which are directed to vehicle seats having configurations that include a cranium support portion and a cervical spine support portion. Certain patents describe the incorporation of various crush zones in the form of air bladders in the seat back.
Segmented seat backs with head rests in which the upper portion of the seat back and head rest are adjustable are also known. Seat backs are known having a bottom portion and a top portion, with a head rest attached to the top portion. The top portion and head rest can be pivoted toward the individual's head to purportedly minimize injuries from a rear end collision that might otherwise result. Seat backs are also known that include an upper portion having a head rest and a lower portion. The seat back upper and lower portions can be pivoted with respect to each other, thereby also changing the position of the head rest. Biasing the upper portion of the seat back and the attached head rest towards a forward position supports and contacts a person. Seat backs have also been provided with a joint so that an upper part of the seat (and head rest attached thereto) can be inclined relative to the lower part of the seat. Inclination of the upper part is adjusted based upon the inclination of the lower part.
Vehicle seats with adjustable seat back contours, particularly in the upper back and neck region and head area are also known. Pneumatic energy absorbing seat assemblies are known in which the contour of the seat assembly can be adjusted by inflating various lumbar and thoracic bladders in the seat. An integrated head restraint system that features a damping mechanism in such seats is also known. In such seats, a head restraint member is adjustable forwardly and rearwardly by inflating and deflating the thoracic bladder.
In addition, it is also known to provide communication between a head rest and a seat back. A seat back and head rest system is known in which when the seat back is in a generally upright position, the head rest is back and out of the way of a passenger's head. When the seat is moved to a recline position, the head rest is rotated forward to support the head. A seat back and head restraint system is also known that adjusts the position of the head restraint depending upon the degree of recline of the seat back.
More recently, designs have focused on changing the position of a head rest and the configuration of a seat back upon a rear end collision. A seat mechanism that couples a lumbar support to a head rest is known. The mechanism apparently disengages the lumbar support from the seat back frame in the event of a rear end collision. Force is transmitted to the head rest to move the head rest forward in closer proximity to the occupant. In addition, a seat and head rest assembly is known having a seat back upper portion push-out device. Upon application of a force such as from a rear end collision, to the front of a seat, a lever is displaced which in turn urges a pushing member forward, toward the shoulder region of the seat occupant. The movement of the lever also results in forward movement of the head rest.
In summary, vehicle seats with adjustment provisions are well known in the art. And, designing vehicle seats with improved safety features has long been a concern for artisans. In addition, numerous seat, head rest, and seat back configurations have been developed that enable a user to adjust the relative positions of the seat, head rest, and seat back contour.
As efforts to improve occupant comfort continue, vehicle seats have been provided with an increasing array of adjustments. In addition, it is typical for many or all of these adjustments to be powered, or made automatically by the vehicle upon sensing or otherwise determining the identity of the seat occupant. However, many of these adjustments are interrelated, such that adjustment of one parameter affects other parameters.
Safety concerns may dictate that head rests be positioned at specific locations relative to the head of a seat occupant. For example, new legislation set forth in 49 CFR Part 571, and specifically 49 CFR Section 571.202, will likely require front and rear head rests in vehicles to be directly proximate to the back of an occupant's head. Requiring a particular position for a head rest will likely result in an increased user preference that the seat back be adjusted to accommodate the dictated position of the head rest. This concern may be aggravated when a seat is used by different people, and so, the dictated position of the head rest may change from user to user. Although manual adjustment of a seat back is possible and known in the art, it would be beneficial to provide a vehicle seat in which the configuration of the seat back was automatically adjusted based upon the position of the head rest.
The provision of a head rest that is relatively tall and thick, may serve to improve user comfort. Utilizing a taller head rest, generally increases the range of user heights that may be accommodated by the seat and head rest assembly. However, as the head rest is raised to accommodate a tall person, the previous configuration of the seat back will typically not match the shape of the back of the tall occupant, since the user's shoulders are higher, and the user's lower back region will be higher than that of the previous seat occupant. And so, the provision of a thicker head rest may promote user comfort by providing support for a tall user's elevated neck and shoulder regions. However, the use of a tall and thick head rest may be undesirable because such head rests may interfere with folding of the seat, such as in clam-shell configurations where seat backs are designed to fold flat. In additions, a bulky head rest, i.e. being relatively tall and thick, may interfere with designs in which the seat back can be stowed away.
Although satisfactory in many respects, the prior art does not provide a seat configuration in which the contour of a seat back is automatically adjusted based upon changes in the position of a head rest. That is, although it is known to change the position of a head rest based upon changes in the position of the seat or seat back, the prior art does not provide a vehicle seat configuration in which the position or contour of a seat back is changed based upon the position of the head rest. Specifically, it would be desirable to provide a vehicle seat having provisions that adjust the contour of the seat back based upon a change in the position of the head rest, and particularly, upon a change in height of the head rest.
Providing a seat and head rest assembly that could be particularly tailored to match the physical size of the seat occupant should improve comfort for the user, facilitate safety objectives, and enable the use of space saving head rests to thereby enable the seat assembly to be easily stowed or otherwise placed in a variety of folded or reclined states.